4. SOIL Be it deep or shallow, red or black, sand or clay, the soil is the link between the rock core of the earth and the living things on its surface USDA 1957 YEARBOOK OF AGRICULTURE
Agriculture, when treated as an ecosystem, is all about using biological resources, re-cycling energy, multifunctionality, working with succession, biodiversity, and edge effects. This is how we need to be doing agriculture, small scale and in the cities.
The soil food web is a complex, interdependent, mutually beneficial group of organisms ranging in size from bacteria, to fungi (the largest organisms on the planet) to protozoa, to nematodes, microarthropods, worms and beetles. The foodweb develops good soil structure by binding pieces of soil (clay, sand, silt, organic matter, roots) together and by building airways and passageways through the soil. Good movement of air and water are vital to the health of plants and the soil food web itself. While it seems contradictory, good soil structure both allows water to drain from too wet soil and helps soil to hold water when soils start to dry out.